In the oil and gas industry, wellbores are drilled into the earth using drilling rigs, where tubulars are threaded together to form long tubular strings that are inserted into the wellbore to extract the desired fluid. The tubing string is generally suspended in the borehole using a rig floor-mounted spider, such that each new tubular segment or stand may be threaded onto the end of the previous tubular just above the spider. A segment is generally considered one joint of tubing and a stand is generally considered to be two or three joints of tubing combined together. A single joint elevator is commonly used to grip and secure the segment or stand to a hoist to lift the segment or stand into position for threading the tubulars together. Sometimes compensators are used in combination with elevators to reduce the weight of the stand on the connection of the previous string. Once set into position the tubular is rotated with a power tong in the elevator or the entire elevator is allowed to rotate on a swivel with the tubular to allow the connections to be threaded.
In general, single joint elevators are specifically adapted for securing and lifting tubular segments having a conventional connection, such as an internally threaded sleeve that receives and secures an externally threaded end from each of two tubular segments to secure the segments in a generally abutting relationship. The internally threaded sleeve is first threaded onto the end of a first tubular string to form a “box-end.” The externally threaded “pin end” of a second tubular string is then threaded into the box end to complete the connection between the two strings. These elevators have a circumferential shoulder that forms a circle upon closure of the hinged body halves. The shoulder of the elevator engages the shoulder formed between the end of the sleeve and the pipe segment.
Other elevators are specifically adapted for securing and lifting tubular segments having integral connections. These integral connections are generally permanently fixed to each end of the tubular, one end having an internally threaded end or “box-end” and the other end having an externally threaded end or “pin-end”, in a generally abutting relationship. The externally threaded pin-end of the first tubular segment is then threaded into the internally threaded box-end of the tubular string. These elevators generally have a beveled or angled shoulder that forms a circle upon closure of the hinged body halves. The beveled shoulder engages the beveled end of the integral connection of the pipe segment.
At least one challenge encountered by those in the industry is maintaining proper thread integrity of the connections while making up the stand to the string of tubulars. Generally, if the threads of the two connecting tubulars are not properly aligned when the rotation with power tongs begins, the threads of both connections will usually gall or be crushed to a state of non-compliance with industry standards. Typically these connections will have to be removed from the string and discarded or sent back to the manufacturer to be re-threaded. This removal of tubulars and connections from the string can be time consuming and very costly to the rig operator.
Another such challenge to those in the industry is the ability to run segments or stands of very heavy weight tubing. Generally the face of the internally threaded sleeve of a conventional connection rests on the top of the elevator. If the weight of the tubing segment or stand is too great, the friction between the face of the sleeve and the shoulder of the elevator will cause the sleeve to “stick” and the sleeve will not rotate with the tubing. This eventually causes the sleeve to “back-off” or become disconnected from the tubing, possibly allowing the tubing segment or stand to fall to the rig floor.
Yet another challenge is the safety issue that may arise when allowing the single joint to rotate on a swivel. The possibility exists that if the swivel, or the cable holding the swivel, becomes worn or fatigued to the point of failure, the elevator and the tubing would fall to the rig floor.
Therefore, there is a need for an apparatus or system that allows the tubulars to rotate within the elevator with little required torque. This will allow the operator the ability to start the connection of the tubulars by hand with a strap wrench. Thus, the operator may determine whether or not the threads are aligned properly prior to connecting the power tongs and finishing the make-up of the connection.
An objective of the invention is to provide a system comprising multiple rollers that may be seamlessly integrated into existing elevators which encompass inserts or dies to aid in the process of running tubulars.
A further objective is to provide a means of allowing the tubulars to rotate within the elevator without the need for additional pneumatic or hydraulic control lines or actuation.
A further objective is to provide a means to rotate a stand of multiple tubulars that would have been too heavy or unsafe to rotate using conventional methods.
A further objective is to provide a means to run stands of two or three segments of heavy weight tubing instead of a single segment, significantly reducing the time required to run the tubing in the well.
An apparatus of this nature may also significantly reduce the amount of loss time and money due to galled or destroyed connections.
An apparatus of this nature may significantly reduce safety concerns by replacing the need to hang the elevator with cables and a swivel, and also to reduce the possibility of spinning off the upper collar holding the stand on the elevator.
An apparatus of this nature may comprise rollers that encompass a shaft with an arrangement of radial and/or thrust bearings contained within a cylindrical hub.
An apparatus of this nature may comprise rollers that encompass a single ball bearing fixed within a housing.
An apparatus of this nature may typically have rollers that will be oriented vertically or at a specified angle from the vertical in combination with rollers that will be aligned with the vertical or horizontal.
An apparatus of this nature may have interchangeable components that can be replaced in the field thus reducing downtime and ensure proper rotation of the tubular.
These and other advantages will be apparent from the disclosure of the invention(s) contained herein. The above-described embodiments, objectives, and configurations are neither complete nor exhaustive. The Summary of the Invention is neither intended nor should it be construed as being representative of the full extent and scope of the invention. Moreover, references made herein to “the invention” or aspects thereof should be understood to mean certain embodiments of the invention and should not necessarily be construed as limiting all embodiments to a particular description. The invention is set forth in various levels of detail in the Summary of the Invention as well as in the attached drawings and Detailed Description and no limitation as to the scope of the invention is intended by either the inclusion or non-inclusion of elements, components, etc. in this Summary of the Invention. Additional aspects of the invention will become more readily apparent from the Detailed Description particularly when taken together with the drawings.
It should be understood that the drawings are not necessarily to scale, and various dimensions may be altered. In certain instances, details that are not necessary for an understanding of the invention or that render other details difficult to perceive may have been omitted. It should be understood, of course, that the invention is not necessarily limited to the particular embodiments illustrated herein.